Trachionus acarinatus Cui & van Achterberg
Cui, Qian, van Achterberg, Cornelis, Tan, Jiang-Li & Chen, Xue-Xin, 2015, The genus Trachionus Haliday, 1833 (Hymenoptera, Braconidae, Alysiinae) new for China, with description of four new species, ZooKeys 512, pp. 19-37: 21-25
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|Trachionus acarinatus Cui & van Achterberg|
Taxon classification Animalia Hymenoptera Braconidae
Trachionus acarinatus Cui & van Achterberg sp. n. Figs 1, 2-10, 46
Holotype, ♂ (NWUX), "NW. China: Shaanxi, Pingheliang, Ningshan, c. 2000 m, 27.vi.2011, 33°48'N 108°50'E, Jiangli Tan, NWUX". Paratype: 1 ♂ (ZJUH), topotypic and same data.
Scutellum largely smooth and nearly flat; mandible without fourth ventral tooth (Fig. 46); metanotal spine long, its highest point reaching level of tips of setae of scutellum (Fig. 10); propleuron without distinct transverse carina subposteriorly; precoxal sulcus and notauli medium-sized; propodeum gradually lowered posteriorly in lateral view and carina distinctly protruding postero-laterally (Fig. 4); second and third tergites regularly and rather finely striate, with about 60 striae and moderately shiny (Fig. 5). Similar to Trachionus hians (Nees, 1816), but that species has a strong transverse carina at the propleuron subposteriorly (absent or slightly developed in Trachionus acarinatus ); precoxal sulcus and posterior part of notauli wide (medium-sized) and metanotal spine hardly protruding above level of scutellum (protruding far above level of scutellum).
Holotype, male; body length 3.4 mm, forewing length 3.3 mm.
Head. Width of head twice its median length; head dorsally smooth, strongly shiny and largely sparsely setose; antenna with 33 segments, 0.95 × as long as forewing, third segment 1.6 × as long as fourth segment, length of third, fourth and penultimate segments 2.6 ×, 1.7 × and 1.6 × their width, respectively; frons slightly depressed behind antennal sockets and smooth; eye in dorsal view 1.3 × as long as temple; temple in dorsal view directly rounded, smooth and near eye sparsely setose; OOL: diameter of ocellus: POL= 3:1:2; face weakly convex, with distinctly longitudinal carina and down ward pointing setae laterally, largely matt and punctulate; clypeus transverse, with sparse fine punctures and convex; eye glabrous; mandible nearly touching eye, length of malar space 0.1 × basal width of mandible; mandible 1.4 × as long as its maximum width, largely punctate-rugose medially; mandible weakly widened apically, with long and acute triangular middle tooth, and two wide lateral lobes (Fig. 46); maxillary palp 0.9 × height of head.
Mesosoma. Length of mesosoma 1.5 × its height; pronotum laterally mainly smooth except for sparse punctures and rugose posteriorly; propleuron without transverse carina subposteriorly, but slightly developed on left side; epicnemial area largely punctate; precoxal sulcus complete, moderately wide and distinctly crenulate; sternaulus absent; remainder of mesopleuron mostly smooth, dorsally punctate; postpectal carina medially not differentiated from mesosternal rugosity; episternal scrobe large; pleural sulcus finely crenulate dorsally and wider ventrally; mesosternal sulcus medium-sized and moderately crenulate, posteriorly rugose; metapleuron coarsely punctate-reticulate, but dorsally largely smooth; median groove of mesoscutum and notauli complete, narrow and finely crenulate, near posterior end punctate-crenulate; lateral lobes of mesoscutum mostly smooth, shiny, anterior half of middle lobe and area near notauli setose; scutellar sulcus deep and with 2 longitudinal carinae, 0.3 × as long as scutellum; scutellum largely smooth, with few punctures and nearly flat; metanotal spine protruding far above level of scutellum; costulae and double median carina of propodeum distinctly developed but irregular, gradually lowered posteriorly and postero-laterally with protruding carinae; surface of propodeum partly smooth, medially with transverse band of coarse punctate-rugose.
Wings. Pterostigma elliptical; marginal cell of forewing distinctly elongate; vein r issued just before middle of pterostigma (Fig. 2); r:2-SR:3-SR+SR1 = 11:17:69; SR1 curved; 1-CU1:2-CU1 = 1:20; CU1b present; m-cu slightly antefurcal; 1-CU1 hardly widened. Hind wing: M+CU:1-M:1r-m = 28:13:12; cu-a straight; m-cu slightly impressed.
Legs. Hind coxa largely smooth and with long setae; tarsal claws medium-sized (Fig. 9); length of femur, tibia and basitarsus of hind leg 3.9, 9.1 and 5.0 × their width, respectively; all femora widened.
Metasoma. Length of first tergite 1.2 × its apical width, its surface longitudinally coarsely striate, with dorsal carinae converging medially and united in distinct median carina (Fig. 5); second tergite moderately striate, laterally finely striate; third metasomal tergite nearly entirely finely striate, moderately shiny, sparsely setose; combined length of second and third metasomal tergites 0.7 × total length of metasoma (Fig. 6); striae of third tergite with distinct shiny interspaces.
Colour. Black (including mandible); palpi and legs yellow but tarsi and base of hind coxa darkened; tegulae, pterostigma and forewing veins dark brown; hind wing veins pale brown; forewing membrane slightly infuscate, hind wing nearly pellucid.
Forewing length 3.2-3.3 mm, body length 3.3-3.4 mm; antenna with 33 (2 ♂) segments; subposterior transverse carina of propleuron absent or slightly developed; propodeum largely smooth anteriorly or distinctly punctate; paratype has sculpture of metasoma somewhat reduced medio-dorsally.
The name is derived from “a” (Greek for "not, without") and “carina” (Latin for “ridge”) because of the lacking subposterior transverse carina of the propleuron.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.